Field of the Invention
The invention relates to an electrical terminal block, with a terminal housing, with at least two conductor connecting elements which are located in the latter, and with two conductor bars which each have one connecting section and at least one resilient contact section according to the preamble of claim 1. In addition, the invention relates to another block of terminal blocks consisting of at least two terminal blocks which are located next to one another and of at least one plug-in jumper which has at least two legs.
Electrical terminal blocks have been used in the millions for decades in the wiring of electrical installations and devices. The terminals are often latched onto mounting rails which for their part can be located in a plurality in a control cabinet. Moreover, terminal blocks can also be mounted severally as a block of terminal blocks in a wall opening, in particular in an opening in a control cabinet door. This has the advantage that one side of the terminals, the operator side, is accessible from outside the control cabinet without the control cabinet having to be opened, while the other side of the terminal, the connection side, is only accessible when the control cabinet has been opened.
Screw-type terminals or tension spring terminals are often used in terminal blocks as conductor connecting elements. The clamping principle of tension spring terminals is similar to that of screw technology. While in screw terminals a tension sleeve draws the conductor against the conductor bar by actuating the clamping screw, in the tension spring terminal this task is assumed by the tension spring. In addition, insulation piercing connecting devices and leg spring terminals are also being increasingly used; compared to tension spring terminals they have the advantage that to insert a conductor the terminal need not be opened using a tool.
Electrical terminal blocks are often connecting terminals so that they have at least two conductor connecting elements which are electrically connected to one another via an electrically conductive connecting bar, the conductor bar. In addition to this basic type of terminal block which is often also called a feed-through terminal, there are a host of other terminal block types which are adapted specifically to the respective applications. Examples here include protective conductor terminals, isolating blade terminals and installation terminals.
In switching, measurement, test and control engineering, pass-through terminals with an isolating possibility which are therefore in part also called isolating terminals are often used. The isolation possibility which is implemented in this terminal block, i.e., the gap provided in the conductor bar, makes it possible to plug various plugs with different functions into the terminal block, which plugs then make contact with the conductor bar at the gap. In particular, in addition to simple isolating plugs or through-connectors, plugs can also be test plugs which can have special components and can enable the checking of proper operation of the circuit which is connected to the terminal block. Since electrical terminal blocks are usually made disk-shaped, they are generally plugged together with several other electrical terminal blocks into a block of terminal blocks. Then a number of test plugs corresponding to the number of terminal blocks can be plugged into such a block of terminal blocks.
Description of Related Art
Terminal blocks with gaps are used in particular for the connection of current transformers. One important functional feature here consists that a connected current transformer is short-circuited when the secondary circuit is separated from the load.
German Patent Application DE 10 2006 052 894 A1 and corresponding U.S. Pat. No. 7,666,037 B2 disclose a terminal block from which this invention proceeds. This document moreover discloses another test plug and a test terminal block consisting of a plurality of terminal blocks which are located next to one another and of a corresponding number of test plugs. The individual terminal blocks each have two conductor bars whose contact sections make contact with one another when the plug of a test plug is not plugged into the contact region which has been formed by the contact sections. If the plug of a test plug has been fully plugged into the contact region, the two contact sections are separated from one another by the plug, the current flow then being routed via the plug so that a test procedure can be carried out. The terminal block and the assigned test plug then work according to the break-contact principle since the connection between the two conductor bars of the terminal block is being opened when the plug which has two metal sections which are insulated from one another is plugged into the contact region.
In order to ensure reliable and defined contact states when the test plug is being plugged into the contact region, in the known electrical terminal block, the conductor bars are made such that they form two contact regions which are located in succession in the insertion direction of the plug. Making a defined second contact region which is located upstream of the first contact region in the insertion direction of the plug ensures that when the plug is being inserted first a reliable electrical connection between the metal sections of the plug of the test plug and the two conductor bars arises before the first contact region is opened as the plug continues to be inserted and in this way the two conductor bars are electrically separated from one another.
Cross bridging to an adjacent terminal block takes place in this test plug system by plugging the test terminal block into the block of terminal blocks, a plug-in jumper having to be plugged into two adjacent test terminals of the test terminal block.
German Patent Application DE 10 2011 113 333 A1 and corresponding U.S. Pat. No. 9,153,916 B2 also disclose an electrical terminal block in the form of a test terminal. In this terminal block, in the housing there are likewise two conductor connecting elements and two conductor bars. The two conductor bars each have, in addition to one connecting section and a first contact section, also another second contact section. The first contact sections are spaced apart from one another and only when the plug has been plugged in are they electrically conductively connected to one via the plug so that this terminal block operates according to the make-contact principle.
Moreover, there are still two further conductor bar pieces in the housing, in at least one of the conductor bar pieces a recess being formed for plugging in one leg of a plug-in jumper. One of the conductor bar pieces at a time is thus assigned to one of the conductor bars such that the second contact region of one conductor bar makes contact with the assigned conductor bar piece due to the spring force of the conductor bar when a plug has not been plugged in. The conductor bars of the terminal block are then each electrically conductively connected to the conductor connecting element with their connecting section and to the respective conductor bar piece with their second contact section. If a plug of a test plug is being plugged into the contact region, the two conductor bars are deflected such that the second contact section of one conductor bar is spaced apart from the assigned conductor bar piece. Thus the electrical connection between a conductor connecting element and the assigned conductor bar piece is then broken.
In the electrical terminal block known from German Patent Application DE 10 2011 113 333 A1 and corresponding U.S. Pat. No. 9,153,916 B2, when the test plug has not being plugged in, cross bridging to an adjacent terminal block takes place in that one leg of a plug-in jumper at a time is plugged into the recess provided for this purpose in the respective conductor bar pieces of two adjacent terminal blocks so that the two conductor bar pieces are connected to one another via the plug-in jumper. The electrical cross connection between the two conductor connecting elements of two terminal blocks then takes place via the respective conductor bars, the conductor bar pieces and the plugged-in plug-in jumper.